ENCYCLICALS OF JOHN XXIII

On Truth, Unity and Peace (Ad Petri Cathedram)
Promulgated 29 June 1959, the first encyclical of John XXIII's reign discusses the three objectives of truth, unity and peace and indicates how they may be achieved and advanced in a spirit of charity.

On St. John Vianney (Sacerdotii Nostri Primordia)
In this encyclical, promulgated 1 August 1959, Pope John XXIII strives to help the clergy to foster and grow in friendship with Christ as the main source of the joy and fruitfulness of their priestly life.

On the Rosary (Grata Recordatio)
Promulgated 26 September 1959, this encyclical concerns the rosary, prayer for the Church, the missions and international and social problems.

On the Missions (Princeps Pastorum)
Promulgated 26 November 1959, concerns the need of extending God's kingdom to the many parts of the world where missionaries labor zealously that the Church may grow and produce wholesome fruits.

Christianity and Social Progress (Mater Et Magistra)
In this groundbreaking encyclical, promulgated on 15 May 1961, Pope John XXIII says "though the Church's first care must be for souls, she concerns herself too with the exigencies of man's daily life, with his livelihood and education, and his general, temporal welfare and prosperity."

On St. Leo the Great (Aeterna Dei Sapientia)
Promulgated on 11 November 1961, commemorating the fifteenth centennial of the death of Pope St. Leo I and focuses on the See of Peter as the center of Christian unity.

On the Need for Penance (Paenitentiam Agere)
Promulgated on 1 July 1 1962, on the need for the practice of interior and exterior penance.

Peace on Earth (Pacem In Terris)
In his final and perhaps best known encyclical, promulgated 11 April 1963, John XXIII tells us that, "Peace on earth, which all men of every era have most eagerly yearned for, can be firmly established only if the order laid down by God be dutifully observed.